Question

The root(s) of the equation (2x - 3) = $\sqrt{2x^2-2x+21}$are:

• A. 4, -2
• B. 6, -1
• C. 6
• D. -1

Answer 1

The correct option is C

6

On squaring both sides of the equation, we get

4$x^2$ -12x + 9 = 2x${}^2$ - 2x + 21

that gives, 2x${}^2$ - 10x - 12 = 0

on solving, we get x = -1 or 6.

But x = -1 does not satisfy the equation. So the valid root of the equation is x = 6.